Well there is certainly plenty of room for bigger caps in the chassis of this K200B. I've been playing both bass and guitar through it, but i think it will primarily used as a bass cab, so perhaps doubling the caps is in order.
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Kustom K200B, Pics and Question Regarding Speaker Cab
- Thread starter Commodore 64
- Start date
OK The Trace Elliots are in. Cab is now at 4-ohms. It has some serious thump to it. I can't wait to try it at rehearsal where i can really crank it, and also have some real bass players put it through the paces.
Also the speaker code is 137 6903. I'm guessing that means March 1969 for the manufacture date of the speakers. I do believe that would make this a matched cab. I'm pretty sure the speaker cable from the amp head to the cab is also original, too. It's gray and...not modern.
Happy to report that every hole in the Trace Elliot speakers lined up with the posts in the cab, too. Other than that nasty black sticky goo, it was a pretty painless swap.
Also the speaker code is 137 6903. I'm guessing that means March 1969 for the manufacture date of the speakers. I do believe that would make this a matched cab. I'm pretty sure the speaker cable from the amp head to the cab is also original, too. It's gray and...not modern.
Happy to report that every hole in the Trace Elliot speakers lined up with the posts in the cab, too. Other than that nasty black sticky goo, it was a pretty painless swap.
Good to hear things are finally falling in to place on the deal. Actually, the 03 part of the speaker code indicates the week of manufacture, making it January '69 and, of course, the 137 is for CTS. Looks like the real deal. That tar goo is a mess. 
So, if I consider replacing the tantalum caps, with tantalum caps, this gets pricey pretty fast. 35v 33uf tant caps are like 5 bucks a piece, and I need at least 10. Switching to electrolytics saves me about
$150 at mouser for example.
With tants being polarized, I assume I can't just use a film or ceramic cap in their place?
$150 at mouser for example.
With tants being polarized, I assume I can't just use a film or ceramic cap in their place?
I have been (and still am) a Kustom user since 1968 and would like to add to this discussion. Having serviced MANY Kustom amps and cabs over the years, I hope what I present here will be of value.
1. If there is no 60-cycle hum coming from the amp, why replace the filter caps? If you have tread left on your car's tires, do you buy new tires "just because"? But if you must change them, you can up-size, so to speak, the power supply filter caps but don't go overboard. Going from 4,500uf to 10,000 or even more is not going to "filter" the AC component from the DC any better (sonically). However, when turning on the amp, the in-rush current will be significantly greater with "bigger" capacitors, thus stressing the bridge rectifier and power transformer. This is not a good thing.
2. As for replacing out other components (i.e., tantalum caps, resistors, etc.)... why? If the amp is working properly, leave it alone. You will not be able to reduce the hiss and background "noise" that is inherent in the amp's design. It is what it is, and why not keep it as close to original as possible.
3. As for the speaker cabs, they were never designed based on T/S parameters. Case in point... no matter whether Kustom sold a cab for guitar or bass use, or whether the cab had CTS, Jensen, Altec or JBL speakers, the ports were the same. I am sure none of these speakers were a perfect match of the cabinets, nor were the parameters of these speakers equivalent to each other. As for using modern replacements, Eminence Beta 15A speakers are a good match for the 2x15 cabs, but the Eminence Gamma 15 speakers are a bit better match. The reason being that the Kustom 2x15 and, especially, the 2x12 cabs are small internally so speakers with a Qts of less than 0.4 is best (lower is better). Going above 0.4 will cause a loss of bottom end and you'll get a significant response peak in the 100 to 300 Hz region.
4. Kustom 2x15 cabs were designed to be 8 ohms impedance. So, if purchased a K200 head and one 2x15 cab, you'd get a system that put out 50 watts RMS. But you could buy a set up with a K200 head and two 2x15 cabs and it would allow the amp to deliver its maximum of 100 watts RMS. The amp is designed for a minimum load of 4 ohms (to get 100 watts RMS). DO NOT go below 4 ohms. Doing so at louder volumes typically will blow the output driver transistors - I've seen numerous Kustom amps with blown driver transistors due to someone running speaker cabs with an impedance that is too low. This is mostly a problem with amp models other than the K200 and K250 (such as K150, K100, K50, etc.). These other models were design for a minimum of 8 ohms.
I hope this information is useful. Best regards, Keith
1. If there is no 60-cycle hum coming from the amp, why replace the filter caps? If you have tread left on your car's tires, do you buy new tires "just because"? But if you must change them, you can up-size, so to speak, the power supply filter caps but don't go overboard. Going from 4,500uf to 10,000 or even more is not going to "filter" the AC component from the DC any better (sonically). However, when turning on the amp, the in-rush current will be significantly greater with "bigger" capacitors, thus stressing the bridge rectifier and power transformer. This is not a good thing.
2. As for replacing out other components (i.e., tantalum caps, resistors, etc.)... why? If the amp is working properly, leave it alone. You will not be able to reduce the hiss and background "noise" that is inherent in the amp's design. It is what it is, and why not keep it as close to original as possible.
3. As for the speaker cabs, they were never designed based on T/S parameters. Case in point... no matter whether Kustom sold a cab for guitar or bass use, or whether the cab had CTS, Jensen, Altec or JBL speakers, the ports were the same. I am sure none of these speakers were a perfect match of the cabinets, nor were the parameters of these speakers equivalent to each other. As for using modern replacements, Eminence Beta 15A speakers are a good match for the 2x15 cabs, but the Eminence Gamma 15 speakers are a bit better match. The reason being that the Kustom 2x15 and, especially, the 2x12 cabs are small internally so speakers with a Qts of less than 0.4 is best (lower is better). Going above 0.4 will cause a loss of bottom end and you'll get a significant response peak in the 100 to 300 Hz region.
4. Kustom 2x15 cabs were designed to be 8 ohms impedance. So, if purchased a K200 head and one 2x15 cab, you'd get a system that put out 50 watts RMS. But you could buy a set up with a K200 head and two 2x15 cabs and it would allow the amp to deliver its maximum of 100 watts RMS. The amp is designed for a minimum load of 4 ohms (to get 100 watts RMS). DO NOT go below 4 ohms. Doing so at louder volumes typically will blow the output driver transistors - I've seen numerous Kustom amps with blown driver transistors due to someone running speaker cabs with an impedance that is too low. This is mostly a problem with amp models other than the K200 and K250 (such as K150, K100, K50, etc.). These other models were design for a minimum of 8 ohms.
I hope this information is useful. Best regards, Keith
That information is enormously helpful, Keith. I've been vacillating quite a bit about replacing components because it just doesn't seem like this amp has a lot of miles on it. With new filter caps being 22 bucks a piece, I'm not sure it makes sense to change them out just for the sake of change. I don't notice excessive amounts of hiss. Hum, though, is harder to quantify. I use single coils almost exclusively, but I think my Tele is hum canceling in the middle position. I do notice hum in this amp, especially when the treble is cranked. This is 60hz hum:
What I've got may be a bit higher in Frequency. I'll have to get a soundclip.
The speakers I just put in the cab have a Qts of 0.5, FWIW. I have not yet been able to use the cab in a band setting, so I can't say whether it sounds horrible or not. FOr living room practice, it sounds pretty good.
What I've got may be a bit higher in Frequency. I'll have to get a soundclip.
The speakers I just put in the cab have a Qts of 0.5, FWIW. I have not yet been able to use the cab in a band setting, so I can't say whether it sounds horrible or not. FOr living room practice, it sounds pretty good.
Any 60 Hz hum would be present all of the time. It's independent of having any instrument plugged in or where any of the controls are set. If the hum you get occurs with a guitar plugged in and the hum can be affected by turning the volume and/or tone controls, it is coming from the guitar and/or cable.
Yeah kfc333 - We used to road race sports cars years ago. Basic philosophy was "if it ain't broke, don't fix it." Of course, there are always exceptions, but generally the best policy. Thanks for your input. Never can learn too much.
BTW - you should live in Kentucky KFC!
BTW - you should live in Kentucky KFC!
OK, just plugged in my amp. Nothing connected, cranked the volume, treble, bass everything to max. The hiss is not bad at all, though it is there. It seems acceptable to me, given what you've all told me about hiss.
As far as 60hz hum, there is a little, but it's not very noticeable. I think this amp is good to go.
As far as 60hz hum, there is a little, but it's not very noticeable. I think this amp is good to go.
The hiss part sounds normal for a Kustom amp. Did the level of the hum change when you turned all of the controls up versus when they were turned down? If so, that's normal.
Yesterday while playing, I heard a small "pop" and I ended up with a lot more ambient 60hz hum. Also started getting squealies when treble knob is turned past 12 O'Clock. I ordered some new electrolytics, I'll start by replacing those. Any other thoughts?
Caps and cord came yesterday. I need a sanity check.
Pic pretty much sums it up. The switch, I think, changes polarity and is off in the middle. Do I need to put in a new switch or can I just wire it as shown below?
New Mallories are physcially much smaller (I got 5,000uf BTW)
Pic pretty much sums it up. The switch, I think, changes polarity and is off in the middle. Do I need to put in a new switch or can I just wire it as shown below?
New Mallories are physcially much smaller (I got 5,000uf BTW)
I finally put my Kustom 200B through its paces last weekend and forgot to update this thread. After I had ordered new caps, but prior to receiving them, I took the Kustom to rehearsal. We used it for a solid 3 hours for both bass and guitar. Came through with flying colors and great tone. I'm really digging simple SS circuits like this Kustom and my Traynor TS-50. I have 2 pedals, a lovepedal Amp 50 and a Keeley modded DS-1, and they sounded freaking great at rehearsal. The other guy uses a (my) Classic 30 so we had good chance to A/B the tones. With those pedals and my Kustom, I was not missing the tube tone at all. At all.
FYI, as my new filter caps had not arrived and I really wanted to use the Kustom at rehearsal, I threw a hail mary and turned on the Kustom for 2 days straight hoping the caps would reform. I don't know if I'm crazy or had a bad cable when I heard the "pop" followed by hum, but the amp showed no ill effects throughout rehearsal. Great tone and no more hum or hiss than any of the other amps in use.
Swapped in a proper AC cord on Sunday. I had to enlarge the chassis aperture to fit a larger strain-relief plastic thingy, but this was an easy task. Once again the $2.99 I spent on a step drill bit set several years ago at Harbor Freight pays dividends. I ended up leaving the original caps in. The amp sounds great and I felt guilty not letting those old Mallory's get a second lease on life. Now I have 2, $22, 50v, 5,000uf caps sitting in my parts drawer. Guess I'll save them as backup, though I understand it's not good to leave caps unused for significant periods...
FYI, as my new filter caps had not arrived and I really wanted to use the Kustom at rehearsal, I threw a hail mary and turned on the Kustom for 2 days straight hoping the caps would reform. I don't know if I'm crazy or had a bad cable when I heard the "pop" followed by hum, but the amp showed no ill effects throughout rehearsal. Great tone and no more hum or hiss than any of the other amps in use.
Swapped in a proper AC cord on Sunday. I had to enlarge the chassis aperture to fit a larger strain-relief plastic thingy, but this was an easy task. Once again the $2.99 I spent on a step drill bit set several years ago at Harbor Freight pays dividends. I ended up leaving the original caps in. The amp sounds great and I felt guilty not letting those old Mallory's get a second lease on life. Now I have 2, $22, 50v, 5,000uf caps sitting in my parts drawer. Guess I'll save them as backup, though I understand it's not good to leave caps unused for significant periods...
My head sounds great through my 12-inch extension cab with a Cannabis Rex in it too. But there's something about the dual 15s, that really make the hairs on my neck stand up.
